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Fact Checker API

Verify claims with web evidence. Returns sources and verdict. x402 micropayment.

Open source Repository Open in the app JSON README (API)

About

Verify claims with web evidence. Returns sources and verdict. x402 micropayment.

Details

Kind
MCP servers
Topic
Finance & crypto
Publisher
br0ski777
Origin
official
Category
ferramentas
Transport
sse
Version
1.1.0
Last push
2026-09-02T19:55:58Z
Repository state
ativo
Language
TypeScript
License
MIT
Added
2026-08-29 03:01:43
Updated
2026-08-29 03:01:43
Origin id
io.github.Br0ski777/fact-checker

README

# Fact Checker API

[![MCP Server](https://img.shields.io/badge/MCP-server-blue)](https://fact-checker.api.klymax402.com/mcp)
[![x402](https://img.shields.io/badge/payments-x402-6E56CF)](https://x402.org)
[![License: MIT](https://img.shields.io/badge/license-MIT-green)](LICENSE)

Fact-check claims by searching the web and returning relevant evidence snippets. Pay-per-call via [x402](https://x402.org) (USDC on Base L2) -- no API key, no signup, no rate-limit wall.

Part of the [klymax402](https://klymax402.com) marketplace -- 100 x402 micropayment APIs for AI agents, one wallet, USDC on Base.

## Quickstart -- MCP

Add to your MCP client config (Claude Desktop, Cursor, ElizaOS, etc.):

```json
{
  "mcpServers": {
    "fact-checker": {
      "url": "https://fact-checker.api.klymax402.com/mcp"
    }
  }
}
```

## Quickstart -- HTTP (x402)

```bash
curl -X POST "https://fact-checker.api.klymax402.com/api/check" \
  -H "Content-Type: application/json" \
  -d '{"claim":"..."}'
# -> 402 Payment Required, with an x402 payment challenge in the response body
```

Any x402-aware client ([`@x402/fetch`](https://www.npmjs.com/package/@x402/fetch), [`x402-agent-tools`](https://www.npmjs.com/package/x402-agent-tools), ATXP) handles the 402 -> sign -> retry cycle automatically.

## Tools

| Tool | Method | Path | Price | Description |
|---|---|---|---|---|
| `research_check_fact` | POST | `/api/check` | $0.012 | Fact-check a claim by searching for evidence online |

### `research_check_fact`

Use this when you need to verify a factual claim, check if a statement is true, or find evidence supporting or contradicting a claim. Accepts a claim text and returns relevant web snippets, source URLs, and a confidence assessment. Do NOT use for general web scraping — use web_scrape_to_markdown instead. Do NOT use for SEO analysis — use seo_audit_page instead. Do NOT use for sentiment analysis — use sentiment_analyzer instead.

**Parameters**

| Name | Type | Required | Description |
|---|---|---|---|
| `claim` | string | yes | The factual claim to verify (e.g., 'The Eiffel Tower is 330 meters tall') |
| `max_sources` | number | no | Maximum number of sources to return (default: 5, max: 10) |

## Example agent prompts

- "Verify a factual claim, check if a statement is true, or find evidence supporting or contradicting a claim"

## Payment

- Protocol: [x402](https://x402.org) -- HTTP-native pay-per-call, no signup, no API key
- Network: Base L2 (`eip155:8453`)
- Asset: USDC
- Facilitator: Coinbase CDP (primary), PayAI (fallback)

## Part of klymax402

100 x402 micropayment APIs for AI agents -- one wallet, USDC on Base, zero signup.

- Catalog: https://klymax402.com/llms.txt
- Full API reference: https://klymax402.com/llms-full.txt
- Live stats: https://klymax402.com/stats

## License

MIT

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